| 摘要 |
PURPOSE:To relief the characteristic requested for a band pass filter by specifying the direction of coupling of a circulator to decrease the interference between transmission and receiving. CONSTITUTION:A receiving signal f1 of an antenna 1 is applied to a BPF5 via the circulator 3, a signal at an unnecessary band is eliminated and applied to a circulator 6. The circulator 6 has the direction of coupling in the arrow of solid lines, the signal f1 is reflected on a BPF 13 of f2, applied to an amplifier 7 where the signal is amplified and applied to a circulator 8. The circulator 8 has the direction of coupling shown in arrows in solid lines. The signal is applied to a mixer 11 via a BPF10 of f1, mixed with an output of an oscillator 12 and converted into a signal of f2 and applied to the amplifier 7 through a BPF13 of f2 via the circulator 6. The amplified output is applied to the circulator 8, reflected on the BPF10, applied to a BPF9 of f2 and transmitted from an antenna 2 via a circulator 4. The receiving signal f1 of the antenna 2 is transmitted similarly by the signal f2 from the antenna 1. |
